1. Field of the Invention
The present invention relates to a contact terminal and manufacture thereof, which enables stable measurement of electrical characteristics of an electronic component such as semiconductor devices.
2. Background Art
A conventional method of producing a socket will now be described by taking a metal contact (POGO pin) as an example.
FIG. 6 shows a POGO pin. The POGO pin is made up of four major parts; that is, plungers 1 and 2, a barrel 3, and a spring 4. Manufacture of these parts involves high accuracy, and hence these parts cannot be made by means of metal mold casting. The parts are produced individually by means of machining, and the thus-produced parts are finally assembled into a POGO pin shown in FIG. 6.
As shown in FIG. 7, the POGO pin assembled in the manner shown in FIG. 6 is built into plastic, to thereby form a socket. More specifically, POGO pins 7 which are equal in number to external connection terminals 6 (solder balls) of an integrated circuit 5 to be measured are manually built into insulating plastic 8, thereby producing a socket. The thus-produced socket is placed stationary at a position above an I/F board 10. Hereinafter, the integrated circuit is often referred to simply as xe2x80x9cICxe2x80x9d. Although a BGA type is shown as an example here, the IC can be a semiconductor device in general.
The IC 5 is set on the socket, and external force 11 is applied to the IC 5 (by way of a socket cover or through use of a raising tool), wherewith both ends of each POGO pin 7 are depressed. As a result, electrical contact is established at a position between an external connection terminal 6 and the POGO pin 7 as well as at a position between the POGO pin 7 and a metal seat 9 of the I/F board 10. Thus, the electrical characteristics of the IC 5 are measured.
Such a conventional method of manufacturing a socket encounters the following problems:
(1) Constituent parts of a POGO pin are individually produced by means of machining, and the thus-produced parts are assembled into a POGO pin. Hence, per-pin manufacturing costs are very high. For this reason, costs incurred by manufacture of a socket increases in proportion to an increase in the number of external connection terminals of an IC to be measured. Further, manufacturing accuracy (i.e., variations in the position and height of a contact) has limits. As things stand, manufacturing costs of a socket are determined essentially by the number of POGO pins to be built into a socket.
(2) The process of manufacturing a socket involves a number of steps, such as a step of producing individual parts of a POGO pin, a step of assembling the parts into a POGO pin, and a step of building POGO pins into a socket. Further, processing pertaining to all these steps is performed manually. Therefore, a manufacturing time for a socket is protracted.
(3) When a POGO pin has been used over a long period of time, the following problem arises.
As a result of electrical contact having been established between an external connection terminal of an IC (i.e., a solder ball) and a POGO pin, a solder alloy is formed at the tip end of the POGO pin. The solder alloy incurs an increase in resistance between the external connection terminal and the POGO pin, thereby preventing establishment of good electrical contact.
The plunger 1 or the plunger 2 in the POGO pin shown in FIG. 6 is sometimes stuck in the barrel 3 as a mechanical operation failure. As a result, physical contact is not established between the POGO pin 7 and the external connection terminal 6 or between the POGO pin 7 and the metal seat 9. In such a case, an IC may be erroneously determined to be defective. Defective POGO pins must be replaced immediately. However, replacement of a defective POGO pin involves a number of operations, such as specification of a defective POGO pin, disassembly of a socket, and replacement of the defective POGO pin with a non-defective one, thus consuming manpower and time.
When a conventional metal contact such as a POGO pin has been used over a long period of time, the contact is susceptible to various failures, because the contact includes mechanical metal parts. As a result of such a failure, an IC under test cannot be measured correctly, and a defective POGO pin must be replaced.
Procedures for replacement of a POGO pin are roughly broken down as follows:
(i) Since a POGO pin is expensive, a defective pin must be replaced on a per-pin basis.
(ii) A defective POGO pin is specified by means of visual inspection and through use of a tester.
(iii) A socket is removed from a test board.
(iv) The socket is disassembled, and a defective pin is ascertained. The thus-specified pin is replaced with a new one, and the POGO pins are re-assembled into a socket.
(v) The socket is attached to the test board.
Here, attention must be paid to steps (i) and (iv). At the time of replacement of a defective pin, the remaining POGO pins may fall to pieces on the floor. In order to prevent such an accident, close attention must be paid to the POGO pins. As mentioned above, a POGO pin is to be replaced on a per-pin basis. If another pin of the same socket has become defective, the defective pin must be replaced through the same replacement procedures. Thus, maintenance of the socket requires consumption of labor and time than required.
The present invention has been conceived to solve the previously-mentioned drawbacks and is aimed at providing a contact structure which enables stable measurement of electrical characteristics of an electronic component such as semiconductor devices. The present invention also provides a method of manufacturing such contact structure.
According to one aspect of the present invention, a contact terminal element comprises a plate-like heat-resistant insulating member and a plurality of contact terminals formed from conductive resin. The plate-like or film-like heat-resistant insulating member has a plurality of apertures formed therein. The plurality of contact terminals are fitted into the respective apertures of the heat-resistant insulating film, and project from either side of the heat-resistant insulating member.
According to another aspect of the present invention, a contact terminal device comprises a frame member having a hollow section, and a contact terminal element as above is attached to the frame member such that the plurality of contact terminals are located in a hollow section within the frame member.
According to another aspect of the present invention, in a method of manufacturing a contact terminal element, a plate-like or film-like heat-resistant insulating member having a plurality of apertures formed therein is sandwiched between an upper metal mold and a lower metal mold, and each mold has a plurality of cavities for forming a plurality of contact terminals. The upper and lower metal molds are positioned such that each of the cavities of the upper metal mold is brought into mutual communication with each of the cavities of the lower metal mold by way of the apertures of the heat-resistant insulating member. Conductive resin is poured into the thus-communicated cavities. The upper metal mold is separated from the lower metal mold, thereby a contact terminal element is formed.
According to another aspect of the present invention, in a method of manufacturing a contact terminal element, an upper metal mold and a lower metal mold, each having a plurality of cavities for forming a plurality of contact terminals, are positioned such that each of the cavities of the upper metal mold is brought into mutual communication with each of the cavities of the lower metal mold. A plurality of contact terminals are formed by pouring conductive resin to the thus-communicated cavities. The upper metal mold is separated from the lower metal mold. The plurality of contact terminals are separated into pieces. The plurality of contact terminals are fitted into the apertures of the plate-like or film-like heat-resistant insulating member, thereby a contact terminal element is produced.
According to another aspect of the present invention, in a method of manufacturing a contact terminal device, a contact terminal element manufactured by one of the above methods are attached to a frame member, which has a hollow section for receiving an electronic component to be measured.
Other features and advantages of the invention will be apparent from the following description taken in connection with the accompanying drawings.